Alert archive / New Jersey / Flash Flood Watches in 2011

Flash Flood Watch 2, NWS Philadelphia/Mount Holly

May 20, 2011Carbon County, Monroe County, Northampton County, Pennsylvania; 5 counties in New Jersey

NWS Philadelphia/Mount Holly issued this flash flood watch at May 20, 2011, 3:30 AM EDT for Carbon County, Monroe County, Northampton County, Pennsylvania; 5 counties in New Jersey. It took effect at May 20, 2011, 12:00 PM EDT. It was in force for 6 hr.

The area

The counties it named.

The facts

Issued
May 20, 2011, 3:30 AM EDT (07:30 UTC)
In effect from
May 20, 2011, 12:00 PM EDT
Expired
May 20, 2011, 6:08 PM EDT
In force
6 hr
Issued by
NWS Philadelphia/Mount Holly
Flood severity
None

Counties Hunterdon County, NJ, Morris County, NJ, Somerset County, NJ, Sussex County, NJ, Warren County, NJ, Carbon County, PA, Monroe County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 112 km from the middle of the area, began a volume at 07:32 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Brookhaven, NY (KOKX), launched 00:00Z, 7.5 hours before the alert went out and 181 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Brookhaven, NY at 00:00Z on 2011-05-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 72 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Brookhaven, NY at 00:00Z on 2011-05-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 52 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
72 J/kg
Mixed-layer CIN
-107 J/kg
Mixed-layer LCL
1162 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
52 m²/s²
0-3 km storm-relative helicity
102 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.5

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

477 
WGUS61 KPHI 200730
FFAPHI

URGENT - IMMEDIATE BROADCAST REQUESTED
FLOOD WATCH
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
330 AM EDT FRI MAY 20 2011

NJZ001-007>010-PAZ054-055-062-202100-
/O.NEW.KPHI.FF.A.0002.110520T1600Z-110521T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SUSSEX-WARREN-MORRIS-HUNTERDON-SOMERSET-CARBON-MONROE-NORTHAMPTON-
INCLUDING THE CITIES OF...NEWTON...WASHINGTON...MORRISTOWN...
FLEMINGTON...SOMERVILLE...JIM THORPE...STROUDSBURG...BETHLEHEM...
EASTON
330 AM EDT FRI MAY 20 2011

...FLASH FLOOD WATCH IN EFFECT FROM NOON EDT TODAY THROUGH THIS
EVENING...

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY HAS ISSUED A

* FLASH FLOOD WATCH FOR PORTIONS OF NEW JERSEY AND 
  PENNSYLVANIA...INCLUDING THE FOLLOWING AREAS...IN NEW JERSEY...
  HUNTERDON...MORRIS...SOMERSET...SUSSEX AND WARREN. IN 
  PENNSYLVANIA...CARBON...MONROE AND NORTHAMPTON.

* FROM NOON EDT TODAY THROUGH THIS EVENING

* SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND EVENING COULD
  PRODUCE LOCALLY HEAVY RAINFALL. MORE THAN AN INCH OF RAIN COULD
  FALL IN LESS THAN AN HOUR WITH SOME STORMS. WITH SOILS
  SATURATED BY HEAVY RAIN THURSDAY AFTERNOON AND EVENING...THE
  ADDITIONAL RAINFALL COULD RESULT IN FLASH FLOODING.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WATCH MEANS THAT CONDITIONS MAY DEVELOP THAT LEAD
TO FLASH FLOODING. FLASH FLOODING IS A VERY DANGEROUS SITUATION.

YOU SHOULD MONITOR LATER FORECASTS AND BE PREPARED TO TAKE ACTION
SHOULD FLASH FLOOD WARNINGS BE ISSUED.

&&

$$

HAYES
2 follow-up statements
346 
WGUS61 KPHI 201856
FFAPHI

FLOOD WATCH
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
256 PM EDT FRI MAY 20 2011

NJZ001-007>010-PAZ054-055-062-210000-
/O.CON.KPHI.FF.A.0002.000000T0000Z-110521T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SUSSEX-WARREN-MORRIS-HUNTERDON-SOMERSET-CARBON-MONROE-NORTHAMPTON-
INCLUDING THE CITIES OF...NEWTON...WASHINGTON...MORRISTOWN...
FLEMINGTON...SOMERVILLE...JIM THORPE...STROUDSBURG...BETHLEHEM...
EASTON
256 PM EDT FRI MAY 20 2011

...FLASH FLOOD WATCH REMAINS IN EFFECT UNTIL 8 PM EDT THIS
EVENING...

THE FLASH FLOOD WATCH CONTINUES FOR

* PORTIONS OF NEW JERSEY AND PENNSYLVANIA...INCLUDING THE
  FOLLOWING AREAS...IN NEW JERSEY...HUNTERDON...MORRIS...
  SOMERSET...SUSSEX AND WARREN. IN PENNSYLVANIA...CARBON...
  MONROE AND NORTHAMPTON.

* UNTIL 8 PM EDT THIS EVENING

* SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND EVENING COULD 
  PRODUCE LOCALLY HEAVY RAINFALL. MORE THAN AN INCH OF RAIN 
  COULD FALL IN LESS THAN AN HOUR WITH SOME STORMS. WITH SOILS 
  SATURATED BY HEAVY RAIN THURSDAY AFTERNOON AND EVENING...THE 
  ADDITIONAL RAINFALL COULD RESULT IN FLASH FLOODING. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WATCH MEANS THAT CONDITIONS MAY DEVELOP THAT LEAD
TO FLASH FLOODING. FLASH FLOODING IS A VERY DANGEROUS SITUATION.

YOU SHOULD MONITOR LATER FORECASTS AND BE PREPARED TO TAKE ACTION
SHOULD FLASH FLOOD WARNINGS BE ISSUED.

&&

$$

KRUZDLO
482 
WGUS61 KPHI 202208
FFAPHI

FLOOD WATCH
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
608 PM EDT FRI MAY 20 2011


NJZ001-007>010-PAZ054-055-062-202315-
/O.CAN.KPHI.FF.A.0002.000000T0000Z-110521T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SUSSEX-WARREN-MORRIS-HUNTERDON-SOMERSET-CARBON-MONROE-NORTHAMPTON-
INCLUDING THE CITIES OF...NEWTON...WASHINGTON...MORRISTOWN...
FLEMINGTON...SOMERVILLE...JIM THORPE...STROUDSBURG...BETHLEHEM...
EASTON
608 PM EDT FRI MAY 20 2011

...FLASH FLOOD WATCH IS CANCELLED...

THE FLASH FLOOD WATCH FOR PORTIONS OF NEW JERSEY AND PENNSYLVANIA
HAS BEEN CANCELLED. SCATTERED SHOWERS AND AN ISOLATED THUNDERSTORM
ARE STILL POSSIBLE OVER THE AREA THIS EVENING. 

NOTE THAT FLOOD WARNINGS REMAIN IN EFFECT FOR PORTIONS OF THE
PASSAIC AND ROCKAWAY RIVERS IN NORTHERN NEW JERSEY.

$$

The office that day

Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 19, 11:23 PM EDTAreal Flood AdvisoryPHIMonroe, Northampton3 hr
May 20, 2:07 AM EDTAreal Flood AdvisoryPHIMonroe3 hr
May 20, 2:52 AM EDTSpecial Weather StatementPHIMonroe53 min
May 20, 5:45 PM EDTAreal Flood AdvisoryPHIBerks3 hr
May 20, 6:40 PM EDTSpecial Weather StatementPHIMonroe65 min
May 19, 8:36 PM EDTSpecial Weather StatementPHIAtlantic54 min
May 19, 9:26 PM EDTSpecial Weather StatementPHIOcean94 min
May 20, 11:59 AM EDTSpecial Weather StatementPHIBurlington, Camden, Gloucester, Monmouth46 min

Nearby

Flash Flood Watches in New Jersey, 2011Flash Flood Watches in Pennsylvania, 2011Every flash flood watch in 2011

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.